Apparatus for retaining a bone anchor in a bone plate and method for use thereof

Abstract

A medical implant is provided that includes a bone plate having an aperture therethrough. The aperture receives a portion of the bone anchor. A retention mechanism is coupled to the bone plate. The retention mechanism includes a retainer and a biasing member. The biasing member is operatively engaged with at least the retainer. The insertion of the bone anchor in the aperture causes the retainer to move to a first position and elastically deform the biasing member. The biasing member causes the retainer to move to the second position to retain the bone anchor in the bone plate.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates generally to bone plates, and more specifically, the present invention relates to a bone plate containing a retention mechanism for retaining one or more bone anchors in the bone plate and preventing the one or more bone anchors from becoming disengaged from said bone plate. [0002] Various medical procedures involve fixation of boney elements in a patient. In particular, in medical procedures related to the spine, fixation of vertebral bodies may be performed as a result of trauma or a variety of spinal pathologies, abnormalities or disorders. In these medical procedures, fixation of the vertebral bodies is typically used to address instabilities in the spine or in relation to spinal fusion of the vertebral bodies. In this regard, fixation of the vertebral bodies provides mechanical stability and / or to reduce stress or movement in a particular area of the spine. Several mechanisms can be used in fixation of boney eleme...

AI Technical Summary

Benefits of technology

[0006] In one embodiment, a medical implant is provided that uses a bone anchor to attach the medical implant to a boney element. The medical implant includes a bone plate that has an aperture therethrough. The aperture receives at least a portion of the bone anchor. A retention mechanism is coupled to the bone plate. The retention mechanism includes a retainer and a biasing member, and the biasing member is operatively engaged with at least the retainer. The retainer is moveable to and from at least a first position and a second position. The first position allows the bone plate to receive the bone anchor in the aperture. The second position allows the retention mechanism to retain the bone anchor in the bone plate. The insertion of the bone anchor in the aperture causes the retainer to move to the first position and elastically deform the biasing member. The biasing member causes the retainer to move to the second position to retain the bone anchor in the bone plate.

[0007] In another embodiment, a medical implant is provided that uses a first and second bone anchor to attach the medical implant to a boney element. The medical implant includes a bone plate that has a first aperture and a second aperture. The first and second apertures are located through the bone plate. The first aperture receives at least a portion of the first bone anchor. The second aperture receives at least a portion of the second bone anchor. A retention mechanism is coupled to the bone plate. The retention mechanism includes a retainer and a biasing member that engages with at least the retainer. The retainer is moveable to and from at least a first position, a second position and a third position. The first position allows the bone plate to receive the first bone anchor in the first aperture. The second position allows the bone plate to receive the second bone anchor in the second aperture. The third position allows the retention mechanism to retain the first and second bone anchors in the bone plate. The insertion of the first bone anchor in the first aperture causes the retainer to move to the first position and elastically deform the biasing member. The insertion of the second bone anchor in the second aperture causes the retainer to move to the second position and elastically deform the biasing member. The biasing member causes the retainer to move to the third position to retain the first and second bone anchors in the bone plate.

[0008] In even another embodiment, a method for retaining a bone anchor in a medical implant is provided. The method includes providing a bone plate having an aperture located therethrough. The bone plate also includes a retention mechanism that has a retainer and a biasing member. The retainer is moveable to and from at least a first position and a second position. The first position allows the bone plate to receive the bone anchor in the aperture. The second position allows the retention mechanism to retain the bone anchor in the bone plate. The bone anchor is inserted in the aperture. A head of the bone anchor is caused to contact the retention mechanism during the insertion of the bone anchor in the aperture. The retainer is moved to the second position when the head of the bone anchor make contact with the retainer. The biasing member is elastically deformed when the retainer is moved from the first position to the second position. The head of the bone anchor is retained in the aperture when a portion of the bone anchor is positioned below a portion of the retention mechanism. The retainer is moved from the second position to the first position using a force provided from elastic deformation of the biasing member. The bone anchor is retained in the bone plate when the retainer is in the first position.

Problems solved by technology

In particular, these stresses and forces may cause disengagement of the bone anchors from the bone plate.

In addition, the stresses and forces may cause the bone plate or bone anchors to back out and / or pull away from one or more of the vertebral bodies into which the bone plate and bone anchors were attached.

It is particularly undesirable for a bone anchor to pull away from the vertebral body or disengage from the bone plate.

Typically, these bone anchor based retention mechanisms are difficult to manufacture and fabricate, and, as such, increase the costs associated with the manufacturing of the bone anchor.

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